Calcium and magnesium balance in "cerrado" soils and corn development

Abstract

Four Ca:Mg ratios were studied in two "cerrado" soils to find a good balance in soil for root and shoot growth. The soils, DRL (Dark-Red Latosol) and RYL (Red Yellow Latosol) were limed to equal aluminium saturation with different Ca:Mg ratios (4:0, 3:1; 2:2 and 0:4) in combination with various levels of phosphorus and potassium. The experiment was carried out in a greenhouse with corn as the test plant. There was no difference between the behavior of two soils and the effect of the Ca:Mg ratio was the same for all phosphorus and potassium levels. Root and shoot growth decreased drastically as the Ca:Mg ratio decreased from 3:1 to 0:4 showing severe symptoms of Ca deficiency, but no Mg deficiency was observed in the 0:4 treatment during the period of the experiment (40 days). The highest yield was obtained at the 3:1 Ca:Mg ratio with 63 and 70% Ca saturation in DRL and RYL respectively.